Method for manufacturing a semiconductor device having a refractory metal containing film

ABSTRACT

A semiconductor device and a method for manufacturing the same of the present invention in which the semiconductor device is provided with a fuse structure or an electrode pad structure, suppress the copper blowing-out from a copper containing metal film. The semiconductor device comprises a silicon substrate, SiO 2 film provided on the silicon substrate, copper films embedded in the SiO 2  film, TiN films covering an upper face of a boundary region between an upper face of copper films and the copper films, and the SiO 2  film, and SiON films covering an upper face of the TiN films.

This application is based on Japanese patent application NO.2004-077270, the content of which is incorporated hereinto by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a semiconductor device and a method formanufacturing the same.

2. Related Art

In recent years, for the purpose of realizing a highly integratedsemiconductor device, a development concerning miniaturizing for a fusestructure, an interconnect structure, an electrode pad structure or thelike in the semiconductor device is energetically conducted. This kindof technique is described in the Japanese Laid-Open Patent PublicationNo. 2001-284352.

The Japanese Laid-Open Patent Publication No. 2001-284352 describes thesemiconductor device provided with a structure formed in such away as toembed a fuse electrode, an interconnect, an electrode pad, and so forthin a recess formed in an interlayer insulating film, followed by forminga Tin film on an upper portion of them. FIG. 21 shows a sectional viewof the semiconductor device described in the Japanese Laid-Open PatentPublication No. 2001-284352.

In a semiconductor device 2142, fuse electrodes 2146A, 2146B, anelectrode pad 2148, interconnects 2150A, 2150B are embedded in aninterlayer insulating film 2144. And, a metal film 2152 composed of suchas respective TiN film and the like is provided on an upper facethereof.

Further, a cover insulating film 2154 and a polyimide film 2158 isformed on an upper face of the interlayer insulating film 2144 and on ametal film 2152 in this order.

Here, an opening 2156 penetrating a cover insulating film 2154 and apolyimide film 2158 is provided in an upper portion of the electrode pad2148. Further, an opening 2159 penetrating the polyimide film 2158 isalso provided in an upper portion of a fuse structure composed of fuseelectrodes 2146A, 2146B and a metal film 2152.

In the Japanese Laid-Open Patent Publication No. 2001-284352, the effectis described that, according to such composition, furtherminiaturization of the semiconductor device is made to achieve, uponpreventing short-circuiting between the fuse electrode, the interconnectand the electrode pad.

SUMMARY OF THE INVENTION

However, it has now been discovered that the conventional techniquedescribed in the above Japanese Laid-Open Patent Publication No.2001-284352 has still room for improvement in the following point.

Generally, fuse electrodes 2146A, 2146B, an electrode pad 2148 andinterconnects 2150A, 2150B provided on a lower portion of a metal film2152 made of TiN or the like are composed of a copper containing metalfilm. And, the metal film 2152 made of TiN or the like is subjected to apatterning while employing a resist film provided on an upper portion asa mask. After this patterning, the resist film is removed using theoxygen plasma.

On this occasion, when applying plasma oxygen at the time of plasmaremoving of the resist film from above the metal film 2152 made of TiNfilm or the like, a radical oxygen infiltrates up to a copper containingmetal film of an uppermost layer at a position with an insufficientcoverage of the metal film 2152 made of the TiN film or the like(particularly, an interface between an interlayer insulating film and anuppermost of the copper containing metal film), so that, in some cases,the copper blowing-out, which is caused by oxidization of copper,occurs.

For this reason, when copper containing metal films, which compose thefuse electrodes 2146A, 2146B, the electrode pad 2148 and theinterconnects 2150A, 2150B and the like, are in close proximity to eachother, in some cases, a short circuit between the copper containingmetal films occurs.

According to the present invention, there is provided a semiconductordevice comprising a semiconductor substrate, a first insulating filmprovided on the semiconductor substrate, a copper containing metal filmembedded in the first insulating film, a refractory metal containingfilm covering an upper portion of the copper containing metal film, andan upper portion of a boundary portion between the copper containingmetal film and the first insulating film, and a second insulating filmcovering an upper face of the refractory metal containing film.

According to the present invention, there is provided a secondinsulating film covering an upper face of the refractory metalcontaining film, owing to this, the oxidization, which is caused byinfiltration of the oxygen radical into the copper containing metalfilm, is suppressed, so that the copper blowing-out, which takes placecaused by oxidization of the copper containing metal film, issuppressed.

According to the present invention, there is provided a semiconductordevice comprising a semiconductor substrate, a first insulating filmprovided on the semiconductor substrate, a refractory metal containingfilm having a predetermined pattern provided on the first insulatingfilm, a second insulating film provided on an upper face of therefractory metal containing film, and a third insulating film providedon the first insulating film and the second insulating film, wherein thesum of thickness of the second insulating film on the refractory metalcontaining film and thickness of the third insulating film is largerthan thickness of the third insulating film on the first insulatingfilm.

According to the present invention, the sum of the second insulatingfilm thickness on the refractory metal containing film and the thirdinsulating film thickness is larger than the third insulating filmthickness on the first insulating film, therefore, a difference of anindex of reflection of the light between a region where the secondinsulating film resides and a region where the second insulating filmdoes not reside increases, owing to this, alignment properties on theoccasion of a redundancy process are improved.

According to the present invention, there is provided a semiconductordevice comprising a semiconductor substrate, a first insulating filmprovided on the semiconductor substrate, a first insulating filmprovided on the semiconductor substrate, a refractory metal containingfilm having a predetermined pattern provided on the first insulatingfilm, and a second insulating film provided on the first insulating filmand the refractory metal containing film, wherein a thickness of thesecond insulating film on the refractory metal containing film is largerthan a thickness of the second insulating film on the first insulatingfilm.

According to the present invention, a thickness of the second insulatingfilm on the refractory metal containing film is larger than a thicknessof the second insulating film on the first insulating film, therefore, adifference of an index of reflection of the light between a region wherethe refractory metal containing film resides and a region where therefractory metal containing film does not reside increases, owing tothis, alignment property is improved.

According to the present invention, there is provided a method formanufacturing a semiconductor device comprising: forming a firstinsulating film on a semiconductor substrate, embedding a coppercontaining metal film in the first insulating film, forming a refractorymetal containing film covering an upper face of the first insulatingfilm and an upper face of the copper containing metal film, forming asecond insulating film covering an upper face of the refractory metalcontaining film, forming a resist film on an upper face of the secondinsulating film, etching selectively the second insulating film and therefractory metal containing film while employing the resist film as amask, and carrying out a patterning into a shape to cover an upperportion of the copper containing metal film and an upper portion of aboundary portion between the copper containing metal film and the firstinsulating film, and removing the resist film while employing an oxygenplasma.

According to the present invention, since including forming the secondinsulating film covering the upper face of the refractory metalcontaining film, the oxidization, which is caused by infiltration of theoxygen radical into copper containing metal film, is suppressed, so thatthe copper blowing-out, which is caused by the oxidization of the coppercontaining metal film, is suppressed.

According to the present invention, there is provided a method formanufacturing a semiconductor device comprising: forming a firstinsulating film on a semiconductor substrate, embedding a coppercontaining metal film in the first insulating film, forming a refractorymetal containing film covering an upper face of the first insulatingfilm and an upper face of the copper containing metal film, forming asecond insulating film covering an upper face of the refractory metalcontaining film, and forming a resist film on an upper face of thesecond insulating film, etching selectively the second insulating filmwhile employing the resist film as a mask, removing the resist filmwhile employing an oxygen plasma, etching selectively the refractorymetal containing film while employing the second insulating film as amask, and carrying out a patterning into a shape to cover an upperportion of the copper containing metal film and an upper portion of aboundary portion between the copper containing metal film and the firstinsulating film in connection with the second insulating film and therefractory metal containing film.

According to the present invention, the method includes forming thesecond insulating film covering an upper face of the refractory metalcontaining film, therefore, in the removing the resist film uponemploying the oxygen plasma, a diffusion of the radical oxygen issuppressed by the second insulating film, so that the copperblowing-out, which is caused by an oxidization of the copper containingmetal film, is suppressed.

According to the present invention, there is provided a method formanufacturing a semiconductor device comprising: forming a firstinsulating film on a semiconductor substrate, embedding a coppercontaining metal film in the first insulating film, forming a refractorymetal containing film covering an upper face of the first insulatingfilm and an upper face of the copper containing metal film, forming asecond insulating film covering an upper face of the refractory metalcontaining film, forming a resist film on an upper face of the secondinsulating film, etching selectively the second insulating film and therefractory metal containing film while employing the resist film as amask, and carrying out a patterning into a shape to cover an upperportion of the copper containing metal film and an upper portion of aboundary portion between the copper containing metal film and the firstinsulating film, removing the resist film while employing an oxygenplasma, removing the second insulating film, and forming an electrodepad on an upper face of the refractory metal containing film.

According to the present invention, the method includes forming thesecond insulating film covering an upper face of the refractory metalcontaining film, therefore, in the step of removing the resist film uponemploying the oxygen plasma, a diffusion of the radical oxygen issuppressed by the second insulating film, so that a decrease of contactproperty between the copper containing metal film and the refractorymetal film is suppressed.

According to the present invention, there is provided the secondinsulating film covering an upper face of the refractory metalcontaining film, therefore, the copper blowing-out, which is caused byan oxidization of the copper containing metal film, is suppressed.Further, the thickness of the insulating film covering an upper face ofthe refractory metal containing film is large, owing to this, alignmentproperty is improved.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, advantages and features of the presentinvention will be more apparent from the following description taken inconjunction with the accompanying drawings, in which:

FIG. 1 is a plan view schematically showing a fuse structure accordingto a first embodiment;

FIG. 2 is a sectional view schematically showing the fuse structureaccording to the first embodiment;

FIGS. 3A to 3C are process sectional views schematically showing amethod for manufacturing the fuse structure according to the firstembodiment;

FIGS. 4D to 4F are process sectional views schematically showing amethod for manufacturing the fuse structure according to the firstembodiment;

FIG. 5 is a sectional view schematically showing an electrode padstructure according to a second embodiment;

FIGS. 6A to 6C are process sectional views schematically showing amethod for manufacturing the electrode pad structure according to thesecond embodiment;

FIGS. 7D to 7F are process sectional views schematically showing amethod for manufacturing the electrode pad structure according to thesecond embodiment;

FIGS. 8G to 8J are process sectional views schematically showing amethod for manufacturing the electrode pad structure according to thesecond embodiment;

FIGS. 9A to 9C are plan views and a sectional view schematically showinga contrast evaluation method of alignment mark according to theembodiment;

FIG. 10 is a graphical representation showing a contrast evaluationresult of the alignment mark according to a third embodiment;

FIGS. 11A to 11C are process sectional views schematically showing amethod for manufacturing the fuse structure according to a firstcomparison example;

FIGS. 12D to 12E are process sectional views schematically showing amethod for manufacturing the fuse structure according to the firstcomparison example;

FIG. 13 is an enlarged sectional view schematically showing state of thecopper blowing-out of an electrode end portion in a method formanufacturing the fuse structure according to the first comparisonexample;

FIGS. 14A to 14C are process sectional views schematically showing amethod for manufacturing the electrode pad structure according to asecond comparison example;

FIGS. 15D to 15F are process sectional views schematically showing amethod for manufacturing the electrode pad structure according to thesecond comparison example;

FIGS. 16G to 16I are process sectional views schematically showing amethod for manufacturing the electrode pad structure according to thesecond comparison example;

FIGS. 17A to 17C are plan views and a sectional view schematicallyshowing the contrast evaluation method of the alignment mark accordingto a third comparison example;

FIG. 18 is a graphical representation showing a contrast evaluationresult of the alignment mark according to the third comparison example;

FIG. 19 is a plan view showing an evaluation result of condition of thecopper blowing-out in a semiconductor chip provided with the fusestructure according to the first embodiment;

FIGS. 20A to 20D are a plan view and an enlarged view showing anevaluation result of condition of the copper blowing-out in asemiconductor chip provided with the fuse structure according to thefirst comparison example; and

FIG. 21 is a sectional view schematically showing the semiconductordevice provided with the conventional fuse structure.

DETAILED DESCRIPTION OF THE INVENTION

The invention will now be described herein with reference toillustrative embodiments. Those skilled in the art will recognize thatmany alternative embodiments can be accomplished using the teachings ofthe present invention and that the invention is not limited to theembodiments illustrated for explanatory purposed.

In the semiconductor device provided by the present invention, theabove-described second insulating film may be a film including a siliconnitride film, a silicon oxide film or a silicon oxynitride film.According to the configuration, the second insulating film is aninsulating film made of material through which oxygen plasma is hard topass, therefore, it is suppressed that the radical oxygen infiltratesinto the copper containing metal film to cause the oxidization, so thatthe copper blowing-out, which is caused by oxidization of the coppercontaining metal film, is suppressed. Further, according to theconfiguration, alignment property is further improved by the reason thatthe difference of the index of reflection of light is made large betweena region where the second insulating film resides and a region where thesecond insulating film does not reside.

The refractory metal containing film may be a film made of materialincluding not less than one kind selected from a group composed of Ti,TiN, Ta, TaN, W, Mo, Cr and Ni. According to the configuration, it ispossible to use the above described refractory metal containing film asa fuse wiring on the fuse electrode, a barrier metal film on theelectrode pad and cap metal film on the interconnect. Further, accordingto the configuration, an alignment property is further improved by thereason that the difference of the index of reflection of light is madelarge between a region where the refractory metal containing filmresides and a region where the refractory metal containing film does notreside.

The second insulating film may be constituted that the film thickness isnot less than 0.01 μm and not more than 1.0 μm. According to thisconfiguration, the second insulating film is capable of suppressinginfiltrating of oxygen plasma, so that the copper blowing-out, which iscaused by oxidization of the copper containing metal film, issuppressed.

The refractory metal containing film may be constituted that the filmthickness is not less than 0.1 μm and not more than 0.3 μm. According tothe configuration, it is possible to employ the refractory metalcontaining film as the fuse wiring on the fuse electrode, the barriermetal film on the electrode pad and a cap metal film on theinterconnect.

The semiconductor device provided by the present invention may comprisea third insulating film provided on the first insulating film and on thesecond insulating film. According to the configuration, it is possibleto protect the semiconductor device with the third insulating film.

The third insulating film may be a film including the silicon nitridefilm, the silicon oxide film or the silicon oxynitride film. Accordingto the configuration, it is possible to further effectively protect thesemiconductor device with the third insulating film.

The refractory metal containing film may be the fuse wiring, and thecopper containing metal film may be the fuse electrode. According to theconfiguration, it is possible to suppress the copper blowing-out fromthe fuse electrode.

The method for manufacturing the semiconductor device may be providedwith a step of forming solder balls on an upper face of the electrodepad. According to the method, it is possible to provide a BGA structurewith excellent contact property.

The step of forming the second insulating film may include a step offorming the second insulating film by using the plasma method or the CVDmethod. According to the method, a crystal structure of the secondinsulating film becomes dense, therefore, the second insulating film iscapable of more effectively suppressing infiltrating the oxygen plasma,owing to this, the copper blowing-out, which is caused by the coppercontaining metal film oxidization, is further suppressed.

Embodiment

Hereinafter, there will be further described the present invention basedon embodiments, however, the present invention is not limited by theseembodiments.

First Embodiment

FIG. 1 is a plan view schematically showing a fuse structure accordingto the present embodiment. It should be noted that, in FIG. 1, part ofmembers are not shown for convenience of description.

In the fuse structure according to the present embodiment, fuse wirings108 a, 108 b, 118 a and 118 b are provided on an upper face of aninsulating film 104, which is provided on an upper portion of asemiconductor substrate (not shown in the drawings). The fuse wiring 108a and the fuse wiring 108 b are connected to a fuse 102. Likewise, thefuse wiring 118 a and the fuse wiring 118 b are connected to a fuse 112.

On the lower portion of the fuse wirings 108 a, 108 b, 118 a and 118 b,the fuse electrodes 109 a, 109 b, 119 a and 119 b are providedrespectively. In FIG. 1, a laser irradiating region 106 is a regionenclosing the fuse 102 and the fuse 112.

In the case that semiconductor elements (not shown in the drawings)connected to the fuse electrodes 109 a, 109 b, 119 a and 119 b and thelike are defective, the fuse is disconnected by applying a laser lightto the corresponding the fuse 102 or the fuse 112.

FIG. 2 is a sectional view schematically showing A-A′ sectional view ofthe fuse structure according to the embodiment shown in FIG. 1.

On an upper portion of the semiconductor substrate (not shown in thedrawings), a SiO₂ film 134 is provided. In the SiO₂ film 134, copperfilms 138 a, 138 b are embedded. TiN films 132 a, 132 b are provided onan upper face of copper films 138 a, 138 b, and on an upper face of aboundary portion region between the copper films 138 a, 138 b and theSiO₂ film 134.

On an upper face of the TiN films 132 a, 132 b, SiON films 135 a, 135 bare provided. Further, on an upper face of the SiO₂ film 134 and theSiON films 135 a, 135 b, a SiON film 136 is also provided.

According to the configuration, since there is provided the SiON films135 a, 135 b covering an upper face of the TiN films 132 a, 132 b, asdescribed later, on the occasion of removing the resist film on theupper face of the SiON films 135 a, 135 b while using the oxygen plasma,a diffusion of the radical oxygen for a copper film is suppressed by theSiON films 135 a, 135 b, so that the copper blowing-out, which is causedby oxidization of the copper films 138 a, 138 b, is suppressed.

Here, it is preferable that the film thickness of the TiN films 132 a,132 b is made to be, for instance, not less than 0.1 μm and not morethan 0.3 μm. According to the configuration, it is possible topreferably use the TiN films 132 a, 132 b as the fuse wiring.

Further, it is preferable that the film thickness of the SiON films 135a, 135 b, is made to be, for instance, not less than 0.01 μm and notmore than 1.0 μm. According to the composition, the SiON films 135 a,135 b can suppress infiltrating of the oxygen plasma, therefore, thecopper blowing-out, which is caused by oxidization of the copper films138 a, 138 b, is suppressed.

Here, in the present embodiment, TiN films 132 a, 132 b are used as therefractory metal containing film, however, it is not particularlylimited to this matter. For instance, the refractory metal containingfilm may be a film, which is made of materials including not less thanone kind selected from a group composed of Ti, Ta, TaN, W, Mo, Cr and Niother than the TiN films 132 a, 132 b. According to the composition, itis possible to preferably employ the refractory metal containing film asa fuse wiring on the fuse electrode.

Further, in the present embodiment, the SiON films 135 a, 135 b to be asilicon oxynitride is employed as the second insulating film, however,it is not limited specially to this matter. For instance, the secondinsulating film may be a film made of materials including siliconnitride such as SiN and the like or silicon oxide such as SiO₂ and thelike other than the SiON films 135 a, 135 b. According to theconfiguration, the second insulating film is an insulating film made ofmaterial, which makes the oxygen plasma hardly infiltrate, therefore, asdescribed later, when removing the resist film on an upper face of thesecond insulating film, a diffusion of the radical oxygen is suppressedby the second insulating film, the copper blowing-out, which is causedby oxidization of the copper films 138 a, 138 b, is suppressed.

Further, in the present embodiment, there may be further provided a SiONfilm 136, which is provided on the SiO₂ film 134 and the SiON films 135a, 135 b. According to the composition, it is possible to protect thecopper films 138 a, 138 b, the TiN films 132 a, 132 b, the SiON films135 a, 135 b or the like with the SiON film 136.

Further, in the present embodiment, the SiON film 136 to be the siliconoxynitride is employed as a third insulating film, however it is notlimited specially to the matter. For instance, the third insulating filmmay be a film made of material including the silicon nitride such as SiNand the like or the silicon oxide such as SiO₂ and the like other thanthe SiON film 136. According to the configuration, it is possible toeffectively protect the copper films 138 a, 138 b, the TiN films 132 a,132 b and the SiON films 135 a, 135 b and the like with the thirdinsulating film.

It should be noted that, in the present embodiment, the TiN films 132 a,132 b are employed as the fuse wirings and the copper films 138 a, 138 bare employed as the fuse electrodes, however, it is not speciallylimited to the matter. For instance, the TiN films 132 a, 132 b may beemployed as a barrier film, and the copper films 138 a, 138 b may beemployed as an electrode pad. According to the configuration, it ispossible to suppress the copper blowing-out from the electrode pad. Inanother case, the TiN films 132 a, 132 b may be employed as a cap metalfilm, and the copper films 138 a, 138 b may be employed asinterconnects. According to the configuration, it is possible tosuppress the copper blowing-out from the interconnect.

Next, there will be described a method for manufacturing the fusestructure according to the present embodiment. FIGS. 3A to 3C and 4D to4F are process sectional views schematically showing a method formanufacturing the fuse structure according to the embodiment.

As shown in FIG. 3A, in order to manufacture the fuse structure of thepresent embodiment, first, the SiO₂ film 134 is provided on an upperportion of the semiconductor substrate (not shown in the drawings).Next, there is provided a recess portion in the SiO₂ film 134, followedby embedding the copper films 138 a, 138 b on the inner portion of therecess. In embedding of the copper film, for flattening, CMP (ChemicalMechanical Polish) is employed. Further, the TiN film 132 is formed onan upper face of the SiO₂ film 134 and on upper faces of the copperfilms 138 a, 138 b.

Next, as shown in FIG. 3B, the SiON film 135 is formed on an upper faceof the TiN film 132. For instance, the SiON film 135 is formed by aplasma technique or a CVD technique. According to the method, a crystalstructure of the SiON film 135 becomes dense, therefore, as describedlater, the SiON film 135 is capable of more effectively suppressinginfiltrating the oxygen plasma, owing to this, the copper blowing-out,which is caused by the oxidization of the copper films 138 a, 138 b, isfurther suppressed.

Successively, as shown in FIG. 3C, photoresist films 137 a, 137 b withpredetermined pattern are formed on an upper face of the SiON film.Usually, the predetermined pattern is capable of covering a region ofthe copper films 138 a, 138 b with a margin.

And, as shown in FIG. 4D, the respective TiN films 132 a, 132 b and theSiON films 135 a, 135 b are formed by patterning into a shape coveringan upper portion of the copper films 138 a, 138 b and an upper portionof a boundary region between the copper films 138 a, 138 b and the SiO₂film 134, by means of etching of the SiON film 135 and the TiN film 132,using a gas including Cl₂ and BCl₃ as an etching gas with photoresistfilms 137 a, 137 b as masks.

Next, as shown in FIG. 4E, the photoresist films 137 a, 137 b is removedwhile employing the oxygen plasma as an asking gas.

At this time, since the SiON films 135 a, 135 b covering the upper faceof the TiN films 132 a, 132 b reside, in a process removing photoresistfilms 137 a, 137 b while employing the oxygen plasma, the diffusion ofthe radical oxygen is suppressed by the SiON films 135 a, 135 b, so thatthe copper blowing-out, which is caused by the oxidization of the copperfilms 138 a, 138 b, is suppressed.

Successively, as shown in FIG. 4F, the fuse structure described in theembodiment illustrated in the above FIG. 2 is obtained, while formingthe SiON film 136 on an upper portion of the SiO₂ film 134 and the SiONfilms 135 a, 135 b.

According to the manufacturing method of the present embodiment, thesemiconductor device provided with the fuse electrode composed of thecopper films 138 a, 138 b and the like having the fuse wiring composedof the TiN films 132 a, 132 b and the like on an upper face is obtained.At this time, the TiN films 132 a, 132 b are formed on an uppermostlayer of the copper films 138 a, 138 b, after that, the insulating filmsuch as the SiON films 135 a, 135 b or the like are formed, thus, thefuse wiring composed of the TiN films 132 a, 132 b or the like is formedwith those SiON films 135 a, 135 b as a hard mask. Thereafter, the SiONfilm 136 is formed as a protecting film.

In a structure without providing the SiON films 135 a, 135 b, whencarrying out the asking under atmosphere of the oxygen plasma on theoccasion of plasma removing of the photoresist films 137 a, 137 b, theradical oxygen infiltrates up to the uppermost layer of the copper films138 a, 138 b at a position with insufficient coverage (particularly, aninterface between the SiO₂ film 134 and the uppermost layer of thecopper films 138 a, 138 b) of the TiN films 132 a, 132 b, so that, insome cases, the copper blowing-out, which is caused by oxidization ofthe copper films 138 a, 138 b, may occur. A poor coverage of the TiNfilm at the interface between the SiO₂ film 134 and the uppermost layerof the copper films 138 a, 138 b is caused by the fact that the recessof the copper film is generated by the CMP, carried out on the occasionof flattening of copper film embedding.

On the other hand, according to the manufacturing method of the presentembodiment, it is possible to stably manufacture the semiconductordevice provided with a configuration capable of suppressing oxidizationof the copper films 138 a, 138 b and further also suppressing the copperblowing-out caused by the fact that the diffusion of the radical oxygenis suppressed with the SiON films 135 a, 135 b to be the hard mask.

For this reason, according to the manufacturing method, on the occasionof etching of the TiN films 132 a, 132 b, it is possible to suppress thecopper blowing-out caused by oxidization of the copper films 138 a, 138b provided under the fuse wiring composed of the TiN films 132 a, 132 b,so that it is possible to stably manufacture the semiconductor deviceprovided with a configuration capable of preventing an electrical shortbetween fuse wirings composed of the TiN films 132 a, 132 b in proximityto each other.

It should be noted that, in the present embodiment, the patterning ofthe TiN film 132 and the SiON film 135 is carried out with one-stepetching, however, it is not limited especially to the matter. Forinstance, the patterning of the TiN film 132 and the SiON film 135 maybe carried out with two-step etching instead of the patterning of theTiN film 132 and the SiON film 135 be carried out with one-step etching.

In the case of carrying out etching of this two-step, although it is notshown in the drawing, first, with the photoresist films 137 a, 137 b asa mask, the SiON film 135 is made to carry out patterning by the etchingwith etching gas including SF₆, CH₂H₂ and N₂, by this means, the SiONfilms 135 a, 135 b are formed. Next, the photoresist films 137 a, 137 bis removed while employing the oxygen plasma as the ashing gas.Successively, with the SiON films 135 a, 135 b as a mask, the TiN film132 is made to carry out patterning by the etching with etching gasincluding Cl₂ and BCl₂, by this means, the TiN films 132 a, 132 b areformed.

In the case of carrying out the two-step etching, on the occasion ofremoving the photoresist films 137 a, 137 b, while employing the oxygenplasma as the ashing gas, the TiN film 132 is not carried out patterningyet, therefore, it is further suppressed that the radical oxygeninfiltrates into the copper films 138 a, 138 b. For that reason, thereis an advantage that the copper blowing-out is further suppressed.

On the other hand, when carrying out the one-step etching, it ispossible to reduce the number of process, owing to this, there areadvantages that a manufacturing cost is made to decrease, and it ispossible to improve productivity.

FIG. 19 is a plan view showing an evaluation result of condition of thecopper blowing-out in a semiconductor chip provided with the fusestructure according to the present embodiment.

As shown in FIG. 19, in a semiconductor wafer 1901 mounted with thesemiconductor chip provided with the fuse structure according to thepresent embodiment, only very few copper blowing-out 1905 is observed inthe limited copper blowing-out generating region 1903.

FIRST COMPARISON EXAMPLE

FIGS. 20A, 20B, 20C and 20D are plan views and enlarged viewsrespectively showing an evaluation result of condition of the copperblowing-out in the semiconductor chip provided with the fuse structureaccording to the present comparison example described later.

The present inventor has prepared to evaluate the fuse structureprovided with structure without providing a hard cover film composed ofSiON film described above on the fuse wiring composed of the TiN film asfollows:

As shown in FIGS. 20A and 20B, in the semiconductor wafer 2001 (Wno.13and Wno.22) mounted with the semiconductor chip provided with the fusestructure according to the present comparison example described later, alarge number of copper blowing-out 2005 are observed.

FIGS. 20C and 20D are an enlarged observed view in the vicinity of thecopper blowing-out 2005. As shown in FIGS. 20C and 20D, a large numberof the copper blowing-out 2007 a, 2007 b, 2007 c, 2007 d, 2007 e and thelike are observed from end portions of the fuse structure, the electrodepad structure or the interconnect structure. It should be noted that acopper blowing-out 2007 f corresponds to an enlarged observed view ofthe copper blowing-out 2007 e in FIG. 20D.

When carrying out an elemental analysis of the copper blowing-out 2007a, as shown in FIG. 20C, a peak of copper and oxygen is obtained, sothat it has become clear that matter blowing out is a copper oxide.

The inventor has discovered that, based on the experimental data,through pursuing a cause of the copper blowing-out, in some cases, thecopper blowing-out takes place in the following manufacturing process.

FIGS. 11A to 11C and FIGS. 12D and 12E are process sectional viewsschematically showing a method for manufacturing the fuse structureaccording to the present comparison example.

In the manufacturing method of the present comparison example, first, asshown in FIG. 11A, a SiO₂ film 1134 is formed on the semiconductorsubstrate (not shown in the drawings). Subsequently, a recess is formedon an upper face of the SiO₂ film 134 and copper films 1138 a, 1138 bare formed within the recess. Successively, a structure shown in FIG.11A is obtained while forming the TiN film 1132 on the upper face of theSiO₂ film 1134 and on the upper face of the copper films 1138 a, 1138 b.

Next, as shown in FIG. 11B, photoresist films 1137 a, 1137 b withpredetermined pattern are formed on the TiN film 1132.

Successively, as shown in FIG. 11C, TiN films 1132 a, 1132 b are made tocarry out patterning with a method such as etching or the like, whileemploying photoresist film 1137 a, 1137 b as a mask.

Next, as shown in FIG. 12D, the photoresist films 1137 a, 1137 b areremoved, while employing the oxygen plasma or the like as etching gas.

And, as shown in FIG. 12E, a SiON film 1136 is formed in such a way asto coat the SiO₂ films 1134 a, 1134 b and the TiN film 1132.

In the above manufacturing process, on the occasion of plasma removingof the photoresist films 1137 a, 1137 b, the oxygen plasma is applied asetching gas from above the Tin films 1132 a, 1132 b to be the fuse film.

For that reason, as shown in FIG. 12D, the radical oxygen infiltrates upto the copper films 1138 a, 1138 b of the uppermost layer at theposition with insufficient coverage of the TiN films 1132 a, 1132 b, aplurality of the copper blowing-out 1139 a, 1139 b, 1139 c, and 1139 dis caused by the oxidization of the copper.

FIG. 13 is an enlarged sectional view schematically showing the copperblowing-out of an end of the electrode in a method for manufacturing thefuse electrode according to the present comparative example.Specifically, it corresponds to an enlarged sectional view of peripheryof a copper blowing-out portion 1140 shown in FIG. 12D.

In the present comparison example, different from the case of theembodiment, since there is no hard cover film made of SiON or the likeon the TiN films 1132 a, 1132 b, on the occasion of the plasma removingof the photoresist films 1137 a, 1137 b, owing to this, the copperblowing-out 1139 b takes place specially in circumference of a side slitgenerating portion 1142 in the vicinity of an interface between the SiO₂film 1134 to be an interlayer insulating film and the copper films 1138a, 1138 b to be the copper interconnect of the uppermost layer. In thevicinity of the side slit generating portion 1142, since coverage of theTiN films 1132 a, 1132 b is defective, the oxygen plasma is easy toinfiltrate.

Further, the TiN films 1132 a, 1132 b are made of materials in which theoxygen plasma is relatively easy to infiltrate, therefore, in also otherthan those portions, it contributes to generating of copper oxidization.As a result, the volume of the copper films 1138 a, 1138 b is expanded,therefore, a copper blowing-out 1139 b is easy to take place fromperiphery of the interface where a slit is liable to be formed.

And, according to the above-described mechanism, in the case that adistance between the fuse electrodes is near, it contributes to anoccurrence of electrical short between fuse electrodes as shown in astate between a copper blowing-out 1139 b and a copper blowing-out 1139c.

Second Embodiment

FIG. 5 is a sectional view schematically showing an electrode padstructure according to the present embodiment.

An electrode pad structure 224 of the present embodiment is providedwith a multilayer film 211 on a silicon substrate 210. An interlayerinsulating film 214 is provided on an upper face of the multilayer film211. And, a copper interconnect 212 is embedded within the interlayerinsulating film 214. A TiN film 215 is provided on an upper face of thecopper interconnect 212 and on an upper face of the interlayerinsulating film 214. A pad metal film 217 is provided on the upper faceof the TiN film 215.

A TiN film 221 is provided on an upper face of the pad metal film 217.An opening is provided on portion of the TiN film 221; in the opening,an upper face of the pad metal film 217 is connected to a solder ball220. Further, a polyimide film 218 covering a multilayered film of theTiN film 215, the pad metal film 217 and the TiN film 221, and coveringa side face of part of the solder ball 220 are provided on theinterlayer insulating film 214.

FIGS. 6A to 6C, 7D to 7F and 8G to 8J are process sectional viewsschematically showing the electrode pad structure according to thepresent embodiment.

Next, there will be described a method for manufacturing the electrodepad of the present embodiment.

As shown in FIG. 6A, in order to manufacture the electrode pad structureof the present embodiment, first, a multilayered film 211 composed of amultilayer interconnect structure or the like is formed on a siliconsubstrate 210. Subsequently, a copper interconnect 212 is formed on themultilayered film 211. And, a periphery of the copper interconnect 212is made to coat with an interlayer insulating film 214 made of SiON orthe like. And, a via hole 222 is provided while carrying out patterningof the interlayer insulating film 214, to expose at least portion of anupper face of the copper interconnect 212.

Next, as shown in FIG. 6B, the TiN film 215 and a hard mask 216 made ofSiON or the like are formed in this order, in such a way as to coat theexposed upper face of the copper interconnect 212 and the upper face ofthe interlayer insulating film 214 made of SiON and the like.

Successively, as shown in FIG. 6C, a photoresist film 237 is formed onportion of an upper face of the hard mask made of SiON or the like witha shape so as to fill the via hole 222.

And, as shown in FIG. 7D, the TiN film 215 and a hard mask 216 composedof the TiN film 215 and SiON and the like are patterned with a methodsuch as an etching or the like, while employing a photoresist film 237as a mask, and employing gas including Cl₂ and BCl₂ as an etching gas.

Next, as shown in FIG. 7E, the photoresist film 237 is removed whileemploying the oxygen plasma as an asking gas.

Here, the hard mask 216 made of SiON or the like provided on an upperface of the TiN film 215 is made of material, which causes the oxygenplasma to hardly take place infiltrating than the TiN film 215. For thisreason, a diffusion of the radical oxygen is suppressed with the hardmask 216 made of SiON or the like.

As a result, a quantity of the radical oxygen, which infiltrates up to asurface of the copper interconnect 212, decreases, so that oxidizationis suppressed on the upper face of the copper interconnect 212. For thisreason, good contact property between the surface of the copperinterconnect 212 and the TiN film 215 is maintained.

And, as shown in FIG. 7F, the hard mask 216 made of SiON or the likeprovided on an upper face of the Tin film 215 is removed with a methodsuch as the etching.

Successively, as shown in FIG. 8G, a pad metal film 217, and a TiN film221 are formed on an upper face of the TiN film 215 in this order.

And, as shown in FIG. 8H, a periphery of the TiN film 215, the pad metalfilm 217 and the TiN film 218 is coated with a polyimide film 218.Further, at least portion of an upper face of the TiN film 221 is madeto expose while providing an opening 219 to carry out patterning of thepolyimide film 218.

Next, as shown in FIG. 8I, a portion of an upper face of the pad metalfilm 217 is made to expose while carrying out patterning of the exposedportion of the TiN film 221 with a method such as etching or the like.

Successively, as shown in FIG. 8J, a pad electrode structure 224 asdescribed above is obtained, while forming a solder ball in such away asto connect to the exposed portion of the pad metal film 217.

According to the method, a diffusion of the radical oxygen is suppressedwith a hard mask 216 made of SiON or the like, therefore, a quantity ofthe radical oxygen, which infiltrates up to a surface of the copperinterconnect 212, decreases, so that oxidization on the upper face ofthe copper interconnect 212 is suppressed. For that reason, excellentcontact property between the surface of the copper interconnect 212 andthe TiN film 215 is maintained, thus it is possible to provide a BGAstructure with the excellent contact property.

25

SECOND COMPARISON EXAMPLE

FIGS. 14A to 14C, 15D to 15F and 16G to 16I are process sectional viewsschematically showing a method for manufacturing the electrode padstructure according to the present comparison example.

The inventor has made up of the electrode pad structure to evaluate,employed with a manufacturing method without providing a hard maskcomposed of SiON film or the like on a barrier metal film composed ofthe TiN film described above, described as follows:

In the manufacturing method of the present comparison example, first, asshown in FIG. 14A, on a silicon semiconductor substrate 1210, amultilayered film 1211 provided with a multilayered interconnectstructure is formed. Subsequently, on the multilayer film 1211, a copperinterconnect 1212 is formed. And, a periphery of the copper interconnect1212 is coated with an interlayer insulating film 1214. And, at leastportion of an upper face of the copper interconnect 1212 is made toexpose, while providing a via hole 1222 to carry out patterning of theinterlayer insulating film 1214.

Subsequently, as shown in FIG. 14B, a TiN film 1215 is formed so as tocoat the exposed upper face of the copper interconnect 1212 and theupper face of the interlayer insulating film 1214.

Successively, as shown in FIG. 14C, a photoresist film 1237 is formed ona portion of an upper face of the TiN film 1215 in such a shape so as tofill the via hole 1222.

And, as shown in FIG. 15D, the TiN film 1215 is patterned in such amethod as an etching or the like, while employing a resist film 1237 asa mask.

Next, as shown in FIG. 15E, the photoresist film 1237 is removed whileemploying the oxygen plasma or the like as an etching gas.

Successively, as shown in FIG. 15F, on an upper face of the TiN film1215, a pad metal film 1217 and a TiN film 1221 are formed in thisorder.

And, as shown in FIG. 16G, peripheries of the TiN film 1215, the padmetal film 1217 and the TiN film 1221 are coated with a polyimide film1218. Further, at least portion of an upper face of the TiN film 1221 ismade to expose, while providing an opening 1219 to carry out patterningof the polyimide film 1218.

Next, as shown in FIG. 16H, a portion of an upper face of the pad metalfilm 1217 is made to expose, while carrying out patterning of theexposed portion of the TiN film 1221 in such a method as an etching orthe like.

Successively, as shown in FIG. 16I, a solder ball 1220 is formed, insuch a way as to connect to the exposed portion of the pad metal film1217.

In the present comparison example, different from the embodiment case,since there is no a hard cover film such as a SiON film or the like onthe TiN film 1215, on the occasion of removing the photoresist film1237. In removing the photoresist film 1237, the oxygen plasma or thelike is employed as an etching gas. At this time, the TiN film 1215 ismade of material causing the oxygen plasma to relatively infiltrateeasily. For that reason, the radical oxygen, which infiltrates the TiNfilm 1215, infiltrates up to a surface of the copper interconnect 1212;it contributes to generate an oxidized region 1239 where copper isoxidized.

And, when copper is oxidized, cubical expansion takes place, therefore,it contributes to decrease contact property between the oxidized region1239 of the surface of the copper interconnect 1212 and the TiN film1215.

Third Embodiment

FIGS. 9A to 9C are plan views and a sectional view schematically showinga contrast evaluation method of an alignment mark according to theembodiment.

In order to evaluate alignment property of the fuse electrode accordingto the present embodiment, as shown in FIG. 9A, the respective fusestructures according to the present embodiment described above areprovided as X coordinate alignment marks 1X, 2X, 3X and 4X, and Ycoordinate alignment marks 1Y, 2Y, 3Y and 4Y in the periphery of asemiconductor chip 807.

It should be noted that, as shown in FIG. 9B, in order to reduce ameasurement error, in measurement positions 801, 802, 803, 804 and 805to be five different measurement points on the same semiconductor wafer809, alignment property of the alignment mark of the semiconductor chipis evaluated.

As shown in FIG. 9C, each alignment mark has a structure that a TiN film132 is provided on an upper portion of a fuse electrode (not shown inthe drawings) composed of the copper containing metal film provided onan inside of a recess portion on surface of an upper portion of aninsulating film; and a SiON film 135 is provided on an upper portion ofthe TiN film 132, further, an SiON film 136 is provided on an upperportion of its insulating film (not shown in the drawings) and SiON film135. Here, a thickness of a cover insulating film (sum of thickness ofSiON film 135 and SiON film 136) h1 in an alignment region is madelarger than a thickness of a cover insulating film h2 in a non-alignmentregion. Specifically, h1 is made larger than h2 in 500 Å. That is, athickness of SiON film is made 500 Å.

Measurement of the contrast has been carried out about each alignmentmark made in this way. The contrast of each alignment mark is obtainedin such a method that reflected light is measured upon irradiatingpredetermined wavelength light from above to measure a difference of anindex reflection.

FIG. 10 is a graphical representation showing a contrast evaluationresult of the alignment mark according to the present embodiment. Ahorizontal axis indicates measurement points, and a longitudinal axisindicates a contrast value.

Thus, a contrast value of the alignment mark according to the presentembodiment is degree of about 0.15, so that the contrast value hasreached the reference of about not less than 0.15 to be a contrast valueto become the target, which is required to manufacture a semiconductorelement having an excellent quality with an excellent manufacturingstability.

For that reason, when manufacturing a semiconductor device provided witha fuse structure by a method for manufacturing a fuse structureaccording to the present embodiment described above, in themanufacturing process of the semiconductor device, it becomes easy todisconnect a fuse accurately.

Consequently, in recent years, a fuse electrode composed of a coppercontaining metal film becomes employed instead of a fuse electrodecomposed of a conventional aluminum containing metal film, so, in thecase of manufacturing a semiconductor device provided with a fusestructure on the basis of a method for manufacturing a fuse structureaccording to the present embodiment, the above described contrast valuebecomes excellent, thus it is possible to realize excellent alignmentproperty.

That is, a multilayered structure of the TiN film 132, the SiON film 135and the SiON film 136 provided for the fuse structure according to thepresent embodiment, is capable of being employed as an excellentalignment mark. Accordingly, the fuse structure according to the presentembodiment is excellent in the alignment property, and has an advantagethat a correct fuse is easily cut with lasers.

THIRD COMPARISON EXAMPLE

FIGS. 17A to 17C are plan views and a sectional view schematicallyshowing a contrast evaluation method of an alignment mark according tothe present comparison example.

The inventor has made up of a fuse structure to evaluate, provided witha structure without providing a hard cover film composed of the SiONfilm on a fuse wiring composed of the TiN film as follows:

In order to evaluate alignment property of the fuse electrode accordingto the present comparison example, as shown in FIG. 17A, the respectivefuse structures according to the present comparison example describedabove are provided as X coordinate alignment marks 11X, 12X, 13X and14X, and Y coordinate alignment marks 11Y, 12Y, 13Y and 14Y in theperiphery of a semiconductor chip 1407.

It should be noted that, as shown in FIG. 17B, in order to reduce ameasurement error, in measurement positions 1401, 1402, 1403, 1404 and1405 to be five different measurement points on the same semiconductorwafer 1409, alignment property of the alignment mark of thesemiconductor chip is evaluated.

As shown in FIG. 17C, each alignment mark has a structure that a TiNfilm 1132 is provided on an upper portion of a fuse electrode (not shownin the drawings) composed of the copper containing metal film providedon an inside portion of a recess portion on a surface of an upperportion of an insulating film (not shown in the drawings); further, anSiON film 1136 is provided on an upper portion of its insulating film(not shown in the drawings) and the TiN film 1132. Here, a thickness ofa cover insulating film h11 in an alignment region is as same as athickness of a cover insulating film h12 in a non-alignment region.

About each alignment mark produced in this way, a measurement of thecontrast has been carried out. The contrast of each alignment mark isobtained in such a method that reflected light is measured uponirradiating predetermined wavelength light from above to measure adifference of the index reflection.

FIG. 18 is a graphical representation showing a contrast evaluationresult of the alignment mark according to the comparison example. Ahorizontal axis indicates measurement points, and a longitudinal axisindicates contrast value.

Thus, in the present comparison example, different from the embodiment,one more layer of SiON film is not provided on a TiN film, therefore, acontrast value of the alignment mark according to the comparison exampleis of about degree of 0.03, so that the contrast value has not reachedthe reference of about not less than 0.15 to be a contrast value tobecome the target, which is required to manufacture a semiconductorelement having an excellent quality with excellent manufacturingstability.

For that reason, when manufacturing the semiconductor device composed ofthe fuse structure by a method for manufacturing the fuse electrodeaccording to the present comparison example described above, thiscontributes to a state where it becomes difficult to accurately cut afuse.

Conventionally, an aluminum containing metal film excellent in alignmentproperty was used as a material of the fuse electrode, for that reason,the alignment property was relatively excellent, even though fuseelectrodes composed of the structure described above are used asalignment marks.

On the other hand, in recent years, fuse electrodes composed of a coppercontaining metal film become employed instead of fuse electrodescomposed of a conventional aluminum containing metal film, accordingly,an alignment property deterioration caused by the above describedcontrast value lowering becomes remarkable.

For that reason, as the present comparison example, in a case that afuse electrode composed of a copper containing metal film is provided ona lower portion, it becomes apparent that a contrast value of analignment mark is insufficient.

As described above, the present invention has explained based on theembodiment. Strictly, the embodiment is illustration only, and variousmodified examples are possible, thus, those skilled in the art mayunderstand that such modified examples fall within the scope of thepresent invention.

It is apparent that the present invention is not limited to the aboveembodiment that modified and changed without departing from the scopeand sprit of the invention.

1. A method for manufacturing a semiconductor device comprising: forminga first insulating film on a semiconductor substrate; embedding a coppercontaining metal film in said first insulating film; forming arefractory metal containing film covering an upper face of said firstinsulating film and an upper face of said copper containing metal film;forming a second insulating film covering an upper face of saidrefractory metal containing film, said second insulating film being madeof material through which oxygen plasma is hard to pass; forming aresist film on an upper face of said second insulating film, etchingselectively said second insulating film and said refractory metalcontaining film while employing said resist film as a mask, and carryingout a patterning into a shape to cover an upper portion of said coppercontaining metal film and an upper portion of a boundary portion betweensaid copper containing metal film and said first insulating film; andremoving said resist film while employing an oxygen plasma.
 2. Themethod for manufacturing a semiconductor device according to claim 1,wherein said forming said second insulating film includes forming saidsecond insulating film by plasma technique or CVD technique.
 3. Themethod for manufacturing a semiconductor device according to claim 1,wherein said second insulating film includes a silicon nitride film, asilicon oxide film or a silicon oxynitride film.
 4. A method formanufacturing a semiconductor device comprising: forming a firstinsulating film on a semiconductor substrate; embedding a coppercontaining metal film in said first insulating film; forming arefractory metal containing film covering an upper face of said firstinsulating film and an upper face of said copper containing metal film;forming a second insulating film covering an upper face of saidrefractory metal containing film, said second insulating film being madeof material through which oxygen plasma is hard to pass; and forming aresist film on an upper face of said second insulating film, etchingselectively said second insulating film while employing said resist filmas a mask, removing said resist film while employing an oxygen plasma,etching selectively said refractory metal containing film whileemploying said second insulating film as a mask, and carrying out apatterning into a shape to cover an upper portion of said coppercontaining metal film and an upper portion of a boundary portion betweensaid copper containing metal film and said first insulating film inconnection with said second insulating film and said refractory metalcontaining film.
 5. The method for manufacturing a semiconductor deviceaccording to claim 4, wherein said forming said second insulating filmincludes forming said second insulating film by plasma technique or CVDtechnique.
 6. The method for manufacturing a semiconductor deviceaccording to claim 4, wherein said second insulating film includes asilicon nitride film, a silicon oxide film or a silicon oxynitride film.